measuring relative altitude using two BMP390 sensors

Dear Community

I have a requirement to measure the relative altitude between two points in space. a module containing BMP390 sensor will be deployed at a certain height. the module will communicate the absolute pressure measured to a handheld device at ground level using wireless communication. the handheld device will have a BMP390 sensor built-in which will measure the barometric pressure at ground level. the handheld device will calculate the relative altitude between the two devices using the difference in pressure reported by the two devices. the absolute accuracy of BMP390 sensor in altitude is approximately 4m whereas the relative accuracy in altitude is approximately 250mm.

I need my measurement accuracy to be +/-250mm. is there a way I can marry the two sensors and offset the absolute accuracy error?

there will be multiple devices deployed at the same time. an operator walking on the ground with the handheld device should be able to estimate the height of each of them. this means maintaining a table of calibration offset for each sensor is not very user-friendly.

the maximum height I need to measure is 30m.

pls advice me on what I can do to accomplish this?

Mahi

Best reply by BSTRobin

Hello mahivarma，

Calibration: under the same air pressure environment, read the air pressure value of the sensor and compare it with the value measured by the standard barometer to get an offset. The offset will be subtracted from the data read later.

After the two sensors are calibrated, you can test the height difference in your application. We haven't done such a test, so we can't determine the accuracy of using two sensors to measure the height difference. You can have a try.

In addition, even if there is still a drift after the two sensors are calibrated, there is about ±0.16 hPa drift in 12 months, so the two sensors need to be recalibrated after a period of time.

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